Use the alimony calculator on SterlingLawyers. Com to estimate monthly alimony payments in Illinois based on income and other factors.This Illinois alimony calculator uses the Illinois alimony formula to calculate maintenance payments. The Illinois Child Support Estimator is designed to provide an estimate of a child support amount in accordance with the Illinois child support guidelines. Use the Alimony Calculator above to estimate your spousal maintenance in the state of Illinois. Illinois courts also use a new formula to calculate alimony payments. In a divorce money is also evidence of income which can determine child support and maintenance (formerly known as alimony). Check out our five steps process now! Before calculating a maintenance award in Illinois, judges must first decide if maintenance is appropriate given the parties' circumstances. Illinois courts also use a new formula to calculate alimony payments.